/opengl/docs/man_pages/hardcopy/gl/html/gl/

Transcription

1 Index of /opengl/docs/man_pages/hardcopy/gl/html/gl/ Index of /opengl/docs/man_pages/hardcopy/gl/html/gl/ Name Last modified Size Description Parent Directory accum.html 09-Sep-97 16:16 5K alphafunc.html 09-Sep-97 16:16 3K aretexturesresident.h+ 09-Sep-97 16:17 3K arrayelement.html 09-Sep-97 16:17 2K begin.html 09-Sep-97 16:17 8K bindtexture.html 09-Sep-97 16:18 4K bitmap.html 09-Sep-97 16:17 4K blendcolorext.html 09-Sep-97 16:16 1K blendfunc.html 09-Sep-97 16:17 8K calllist.html 09-Sep-97 16:17 2K calllists.html 09-Sep-97 16:17 6K clear.html 09-Sep-97 16:16 3K clearaccum.html 09-Sep-97 16:17 1K clearcolor.html 09-Sep-97 16:17 1K cleardepth.html 09-Sep-97 16:18 1K clearindex.html 09-Sep-97 16:17 1K clearstencil.html 09-Sep-97 16:16 1K clipplane.html 09-Sep-97 16:17 3K color.html 09-Sep-97 16:16 7K colormask.html 09-Sep-97 16:17 1K colormaterial.html 09-Sep-97 16:17 3K colorpointer.html 09-Sep-97 16:17 4K copypixels.html 09-Sep-97 16:17 9K (1 of 5) [24/09/ :49:30]

2 Index of /opengl/docs/man_pages/hardcopy/gl/html/gl/ copyteximage1d.html 09-Sep-97 16:17 5K copyteximage2d.html 09-Sep-97 16:17 5K copytexsubimage1d.htm+ 09-Sep-97 16:18 copytexsubimage2d.htm+ 09-Sep-97 16:18 4K 5K cullface.html 09-Sep-97 16:17 2K deletelists.html 09-Sep-97 16:18 1K deletetextures.html 09-Sep-97 16:17 1K depthfunc.html 09-Sep-97 16:17 2K depthmask.html 09-Sep-97 16:17 1K depthrange.html 09-Sep-97 16:17 2K drawarrays.html 09-Sep-97 16:16 3K drawbuffer.html 09-Sep-97 16:17 4K drawelements.html 09-Sep-97 16:17 3K drawpixels.html 09-Sep-97 16:17 17K edgeflag.html 09-Sep-97 16:16 2K edgeflagpointer.html 09-Sep-97 16:17 3K enable.html 09-Sep-97 16:17 13K enableclientstate.htm+ 09-Sep-97 16:18 3K evalcoord.html 09-Sep-97 16:17 7K evalmesh.html 09-Sep-97 16:17 5K evalpoint.html 09-Sep-97 16:17 2K feedbackbuffer.html 09-Sep-97 16:17 8K finish.html 09-Sep-97 16:16 1K flush.html 09-Sep-97 16:17 1K fog.html 09-Sep-97 16:18 6K frontface.html 09-Sep-97 16:17 2K frustum.html 09-Sep-97 16:17 3K genlists.html 09-Sep-97 16:17 1K gentextures.html 09-Sep-97 16:18 2K (2 of 5) [24/09/ :49:30]

3 Index of /opengl/docs/man_pages/hardcopy/gl/html/gl/ get.html 09-Sep-97 16:18 61K getclipplane.html 09-Sep-97 16:17 1K geterror.html 09-Sep-97 16:17 3K getlight.html 09-Sep-97 16:17 7K getmap.html 09-Sep-97 16:17 4K getmaterial.html 09-Sep-97 16:17 4K getpixelmap.html 09-Sep-97 16:17 3K getpointerv.html 09-Sep-97 16:17 1K getpolygonstipple.htm+ 09-Sep-97 16:17 1K getstring.html 09-Sep-97 16:17 3K gettexenv.html 09-Sep-97 16:17 2K gettexgen.html 09-Sep-97 16:17 3K getteximage.html 09-Sep-97 16:17 5K gettexlevelparameter.+ 09-Sep-97 16:17 5K gettexparameter.html 09-Sep-97 16:18 4K hint.html 09-Sep-97 16:17 3K index_.html 09-Sep-97 16:17 2K indexmask.html 09-Sep-97 16:17 1K indexpointer.html 09-Sep-97 16:17 4K initnames.html 09-Sep-97 16:17 1K interleavedarrays.htm+ 09-Sep-97 16:17 3K isenabled.html 09-Sep-97 16:17 4K islist.html 09-Sep-97 16:16 1K istexture.html 09-Sep-97 16:17 1K light.html 09-Sep-97 16:17 10K lightmodel.html 09-Sep-97 16:17 6K linestipple.html 09-Sep-97 16:17 3K linewidth.html 09-Sep-97 16:17 3K listbase.html 09-Sep-97 16:17 1K (3 of 5) [24/09/ :49:30]

4 Index of /opengl/docs/man_pages/hardcopy/gl/html/gl/ loadidentity.html 09-Sep-97 16:17 1K loadmatrix.html 09-Sep-97 16:17 2K loadname.html 09-Sep-97 16:17 1K logicop.html 09-Sep-97 16:16 4K map1.html 09-Sep-97 16:17 9K map2.html 09-Sep-97 16:17 12K mapgrid.html 09-Sep-97 16:17 3K material.html 09-Sep-97 16:17 7K matrixmode.html 09-Sep-97 16:17 1K multmatrix.html 09-Sep-97 16:17 3K newlist.html 09-Sep-97 16:16 5K normal.html 09-Sep-97 16:17 3K normalpointer.html 09-Sep-97 16:17 4K ortho.html 09-Sep-97 16:17 3K passthrough.html 09-Sep-97 16:17 1K pixelmap.html 09-Sep-97 16:16 8K pixelstore.html 09-Sep-97 16:17 14K pixeltransfer.html 09-Sep-97 16:17 13K pixelzoom.html 09-Sep-97 16:17 1K pointsize.html 09-Sep-97 16:17 4K polygonmode.html 09-Sep-97 16:18 3K polygonoffset.html 09-Sep-97 16:17 2K polygonstipple.html 09-Sep-97 16:17 2K prioritizetextures.ht+ 09-Sep-97 16:17 3K pushattrib.html 09-Sep-97 16:17 10K pushclientattrib.html 09-Sep-97 16:17 3K pushmatrix.html 09-Sep-97 16:17 3K pushname.html 09-Sep-97 16:17 2K rasterpos.html 09-Sep-97 16:17 8K (4 of 5) [24/09/ :49:30]

5 Index of /opengl/docs/man_pages/hardcopy/gl/html/gl/ readbuffer.html 09-Sep-97 16:17 2K readpixels.html 09-Sep-97 16:17 11K rect.html 09-Sep-97 16:17 2K rendermode.html 09-Sep-97 16:17 3K rotate.html 09-Sep-97 16:17 2K scale.html 09-Sep-97 16:16 2K scissor.html 09-Sep-97 16:17 2K selectbuffer.html 09-Sep-97 16:17 4K shademodel.html 09-Sep-97 16:17 3K stencilfunc.html 09-Sep-97 16:17 5K stencilmask.html 09-Sep-97 16:17 1K stencilop.html 09-Sep-97 16:17 5K texcoord.html 09-Sep-97 16:16 5K texcoordpointer.html 09-Sep-97 16:18 4K texenv.html 09-Sep-97 16:17 8K texgen.html 09-Sep-97 16:17 8K teximage1d.html 09-Sep-97 16:17 14K teximage2d.html 09-Sep-97 16:17 14K texparameter.html 09-Sep-97 16:17 11K texsubimage1d.html 09-Sep-97 16:17 5K texsubimage2d.html 09-Sep-97 16:17 5K translate.html 09-Sep-97 16:17 2K vertex.html 09-Sep-97 16:17 4K vertexpointer.html 09-Sep-97 16:17 4K viewport.html 09-Sep-97 16:17 2K (5 of 5) [24/09/ :49:30]

6 NAME glaccum - operate on the accumulation buffer C SPECIFICATION void glaccum( GLenum op, GLfloat value ) PARAMETERS op Specifies the accumulation buffer operation. Symbolic constants GL_ACCUM, GL_LOAD, GL_ADD, GL_MULT, and GL_RETURN are accepted. value Specifies a floating-point value used in the accumulation buffer operation. op determines how value is used. DESCRIPTION The accumulation buffer is an extended-range color buffer. Images are not rendered into it. Rather, images rendered into one of the color buffers are added to the contents of the accumulation buffer after rendering. Effects such as antialiasing (of points, lines, and polygons), motion blur, and depth of field can be created by accumulating images generated with different transformation matrices. Each pixel in the accumulation buffer consists of red, green, blue, and alpha values. The number of bits per component in the accumulation buffer depends on the implementation. You can examine this number by calling glgetintegerv four times, with arguments GL_ACCUM_RED_BITS, GL_ACCUM_GREEN_BITS, GL_ACCUM_BLUE_BITS, and GL_ACCUM_ALPHA_BITS. Regardless of the number of bits per component, the range of values stored by each component is [-1, 1]. The accumulation buffer pixels are mapped one-toone with frame buffer pixels. glaccum operates on the accumulation buffer. The first argument, op, is a symbolic constant that selects an accumulation buffer operation. The second argument, value, is a floating-point value to be used in that operation. Five operations are specified: GL_ACCUM, GL_LOAD, GL_ADD, GL_MULT, and GL_RETURN. (1 of 4) [24/09/ :49:32]

7 All accumulation buffer operations are limited to the area of the current scissor box and applied identically to the red, green, blue, and alpha components of each pixel. If a glaccum operation results in a value outside the range [-1, 1], the contents of an accumulation buffer pixel component are undefined. The operations are as follows: GL_ACCUM GL_LOAD GL_ADD GL_MULT GL_RETURN Obtains R, G, B, and A values from the buffer currently selected for reading (see glreadbuffer). Each component value is divided by 2n-1, where n is the number of bits allocated to each color component in the currently selected buffer. The result is a floating-point value in the range [0, 1], which is multiplied by value and added to the corresponding pixel component in the accumulation buffer, thereby updating the accumulation buffer. Similar to GL_ACCUM, except that the current value in the accumulation buffer is not used in the calculation of the new value. That is, the R, G, B, and A values from the currently selected buffer are divided by 2n-1, multiplied by value, and then stored in the corresponding accumulation buffer cell, overwriting the current value. Adds value to each R, G, B, and A in the accumulation buffer. Multiplies each R, G, B, and A in the accumulation buffer by value and returns the scaled component to its corresponding accumulation buffer location. Transfers accumulation buffer values to the color buffer or buffers currently selected for writing. Each R, G, B, and A component is multiplied by value, then multiplied by 2n-1, clamped to the range [0,2n-1], and stored in the corresponding display buffer cell. The only fragment operations that are applied to this transfer are pixel ownership, scissor, (2 of 4) [24/09/ :49:32]

8 dithering, and color writemasks. To clear the accumulation buffer, call glclearaccum with R, G, B, and A values to set it to, then call glclear with the accumulation buffer enabled. NOTES Only pixels within the current scissor box are updated by a glaccum operation. ERRORS GL_INVALID_ENUM is generated if op is not an accepted value. GL_INVALID_OPERATION is generated if there is no accumulation buffer. GL_INVALID_OPERATION is generated if glaccum is executed between the execution of glbegin and the corresponding execution of glend. ASSOCIATED GETS glget with argument GL_ACCUM_RED_BITS glget with argument GL_ACCUM_GREEN_BITS glget with argument GL_ACCUM_BLUE_BITS glget with argument GL_ACCUM_ALPHA_BITS SEE ALSO glblendfunc, glclear, glclearaccum, glcopypixels, glget, gllogicop, glpixelstore, glpixeltransfer, glreadbuffer, glreadpixels, glscissor, glstencilop (3 of 4) [24/09/ :49:32]

9 (4 of 4) [24/09/ :49:32]

10 NAME glalphafunc - specify the alpha test function C SPECIFICATION void glalphafunc( GLenum func, GLclampf ref ) PARAMETERS func Specifies the alpha comparison function. Symbolic constants GL_NEVER, GL_LESS, GL_EQUAL, GL_LEQUAL, GL_GREATER, GL_NOTEQUAL, GL_GEQUAL, and GL_ALWAYS are accepted. The initial value is GL_ALWAYS. ref Specifies the reference value that incoming alpha values are compared to. This value is clamped to the range 0 through 1, where 0 represents the lowest possible alpha value and 1 the highest possible value. The initial reference value is 0. DESCRIPTION The alpha test discards fragments depending on the outcome of a comparison between an incoming fragment's alpha value and a constant reference value. glalphafunc specifies the reference value and the comparison function. The comparison is performed only if alpha testing is enabled. By default, it is not enabled. (See glenable and gldisable of GL_ALPHA_TEST.) func and ref specify the conditions under which the pixel is drawn. The incoming alpha value is compared to ref using the function specified by func. If the value passes the comparison, the incoming fragment is drawn if it also passes subsequent stencil and depth buffer tests. If the value fails the comparison, no change is made to the frame buffer at that pixel location. The comparison functions are as follows: GL_NEVER GL_LESS GL_EQUAL Never passes. Passes if the incoming alpha value is less than the reference value. Passes if the incoming alpha value is (1 of 3) [24/09/ :49:33]

11 equal to the reference value. GL_LEQUAL GL_GREATER GL_NOTEQUAL GL_GEQUAL GL_ALWAYS Passes if the incoming alpha value is less than or equal to the reference value. Passes if the incoming alpha value is greater than the reference value. Passes if the incoming alpha value is not equal to the reference value. Passes if the incoming alpha value is greater than or equal to the reference value. Always passes (initial value). glalphafunc operates on all pixel write operations, including those resulting from the scan conversion of points, lines, polygons, and bitmaps, and from pixel draw and copy operations. glalphafunc does not affect screen clear operations. NOTES Alpha testing is performed only in RGBA mode. ERRORS GL_INVALID_ENUM is generated if func is not an accepted value. GL_INVALID_OPERATION is generated if glalphafunc is executed between the execution of glbegin and the corresponding execution of glend. ASSOCIATED GETS glget with argument GL_ALPHA_TEST_FUNC glget with argument GL_ALPHA_TEST_REF glisenabled with argument GL_ALPHA_TEST SEE ALSO glblendfunc, glclear, gldepthfunc, glenable, glstencilfunc (2 of 3) [24/09/ :49:33]

12 (3 of 3) [24/09/ :49:33]

13 NAME glaretexturesresident - determine if textures are loaded in texture memory C SPECIFICATION GLboolean glaretexturesresident( GLsizei n, const GLuint *textures, GLboolean *residences ) PARAMETERS n textures Specifies the number of textures to be queried. Specifies an array containing the names of the textures to be queried. residences Specifies an array in which the texture residence status is returned. The residence status of a texture named by an element of textures is returned in the corresponding element of residences. DESCRIPTION GL establishes a ``working set'' of textures that are resident in texture memory. These textures can be bound to a texture target much more efficiently than textures that are not resident. glaretexturesresident queries the texture residence status of the n textures named by the elements of textures. If all the named textures are resident, glaretexturesresident returns GL_TRUE, and the contents of residences are undisturbed. If not all the named textures are resident, glaretexturesresident returns GL_FALSE, and detailed status is returned in the n elements of residences. If an element of residences is GL_TRUE, then the texture named by the corresponding element of textures is resident. The residence status of a single bound texture may also be queried by calling glgettexparameter with the target argument set to the target to which the texture is bound, and the p_name argument set to GL_TEXTURE_RESIDENT. This is the only way that the residence status of a default texture can be queried. (1 of 3) [24/09/ :49:33]

14 NOTES glaretexturesresident is available only if the GL version is 1.1 or greater. glaretexturesresident returns the residency status of the textures at the time of invocation. It does not guarantee that the textures will remain resident at any other time. If textures reside in virtual memory (there is no texture memory), they are considered always resident. Some implementations may not load a texture until the first use of that texture. ERRORS GL_INVALID_VALUE is generated if n is negative. GL_INVALID_VALUE is generated if any element in textures is 0 or does not name a texture. In that case, the function returns GL_FALSE and the contents of residences is indeterminate. GL_INVALID_OPERATION is generated if glaretexturesresident is executed between the execution of glbegin and the corresponding execution of glend. ASSOCIATED GETS glgettexparameter with parameter name GL_TEXTURE_RESIDENT retrieves the residence status of a currently bound texture. SEE ALSO glbindtexture, glgettexparameter, glprioritizetextures, glteximage1d, glteximage2d, gltexparameter (2 of 3) [24/09/ :49:33]

15 (3 of 3) [24/09/ :49:33]

16 NAME glarrayelement - render a vertex using the specified vertex array element C SPECIFICATION void glarrayelement( GLint i ) PARAMETERS i Specifies an index into the enabled vertex data arrays. DESCRIPTION glarrayelement commands are used within glbegin/glend pairs to specify vertex and attribute data for point, line, and polygon primitives. If GL_VERTEX_ARRAY is enabled when glarrayelement is called, a single vertex is drawn, using vertex and attribute data taken from location i of the enabled arrays. If GL_VERTEX_ARRAY is not enabled, no drawing occurs but the attributes corresponding to the enabled arrays are modified. Use glarrayelement to construct primitives by indexing vertex data, rather than by streaming through arrays of data in first-to-last order. Because each call specifies only a single vertex, it is possible to explicitly specify perprimitive attributes such as a single normal per individual triangle. Changes made to array data between the execution of glbegin and the corresponding execution of glend may affect calls to glarrayelement that are made within the same glbegin/glend period in non-sequential ways. That is, a call to glarrayelement that precedes a change to array data may access the changed data, and a call that follows a change to array data may access original data. NOTES glarrayelement is available only if the GL version is 1.1 or greater. glarrayelement is included in display lists. If glarrayelement is entered into a display list, the necessary array data (determined by the array pointers and enables) is also entered into the display list. Because the array (1 of 3) [24/09/ :49:34]

17 pointers and enables are client-side state, their values affect display lists when the lists are created, not when the lists are executed. SEE ALSO glcolorpointer, gldrawarrays, gledgeflagpointer, glgetpointerv, glindexpointer, glinterleavedarrays, glnormalpointer, gltexcoordpointer, glvertexpointer (2 of 3) [24/09/ :49:34]

18 (3 of 3) [24/09/ :49:34]

19 NAME glbegin, glend - delimit the vertices of a primitive or a group of like primitives C SPECIFICATION void glbegin( GLenum mode ) PARAMETERS mode Specifies the primitive or primitives that will be created from vertices presented between glbegin and the subsequent glend. Ten symbolic constants are accepted: GL_POINTS, GL_LINES, GL_LINE_STRIP, GL_LINE_LOOP, GL_TRIANGLES, GL_TRIANGLE_STRIP, GL_TRIANGLE_FAN, GL_QUADS, GL_QUAD_STRIP, and GL_POLYGON. C SPECIFICATION void glend( void ) DESCRIPTION glbegin and glend delimit the vertices that define a primitive or a group of like primitives. glbegin accepts a single argument that specifies in which of ten ways the vertices are interpreted. Taking n as an integer count starting at one, and N as the total number of vertices specified, the interpretations are as follows: GL_POINTS GL_LINES GL_LINE_STRIP GL_LINE_LOOP Treats each vertex as a single point. Vertex n defines point n. N points are drawn. Treats each pair of vertices as an independent line segment. Vertices 2n-1 and 2n define line n. N/2 lines are drawn. Draws a connected group of line segments from the first vertex to the last. Vertices n and n+1 define line n. N-1 lines are drawn. Draws a connected group of line (1 of 4) [24/09/ :49:35]

20 segments from the first vertex to the last, then back to the first. Vertices n and n+1 define line n. The last line, however, is defined by vertices N and 1. N lines are drawn. GL_TRIANGLES GL_TRIANGLE_STRIP GL_TRIANGLE_FAN GL_QUADS GL_QUAD_STRIP GL_POLYGON Treats each triplet of vertices as an independent triangle. Vertices 3n-2, 3n-1, and 3n define triangle n. N/3 triangles are drawn. Draws a connected group of triangles. One triangle is defined for each vertex presented after the first two vertices. For odd n, vertices n, n+1, and n+2 define triangle n. For even n, vertices n+1, n, and n+2 define triangle n. N-2 triangles are drawn. Draws a connected group of triangles. One triangle is defined for each vertex presented after the first two vertices. Vertices 1, n+1, and n+2 define triangle n. N-2 triangles are drawn. Treats each group of four vertices as an independent quadrilateral. Vertices 4n-3, 4n-2, 4n-1, and 4n define quadrilateral n. N/4 quadrilaterals are drawn. Draws a connected group of quadrilaterals. One quadrilateral is defined for each pair of vertices presented after the first pair. Vertices 2n-1, 2n, 2n+2, and 2n+1 define quadrilateral n. N/2-1 quadrilaterals are drawn. Note that the order in which vertices are used to construct a quadrilateral from strip data is different from that used with independent data. Draws a single, convex polygon. Vertices 1 through N define this polygon. (2 of 4) [24/09/ :49:35]

21 Only a subset of GL commands can be used between glbegin and glend. The commands are glvertex, glcolor, glindex, glnormal, gltexcoord, glevalcoord, glevalpoint, glarrayelement, glmaterial, and gledgeflag. Also, it is acceptable to use glcalllist or glcalllists to execute display lists that include only the preceding commands. If any other GL command is executed between glbegin and glend, the error flag is set and the command is ignored. Regardless of the value chosen for mode, there is no limit to the number of vertices that can be defined between glbegin and glend. Lines, triangles, quadrilaterals, and polygons that are incompletely specified are not drawn. Incomplete specification results when either too few vertices are provided to specify even a single primitive or when an incorrect multiple of vertices is specified. The incomplete primitive is ignored; the rest are drawn. The minimum specification of vertices for each primitive is as follows: 1 for a point, 2 for a line, 3 for a triangle, 4 for a quadrilateral, and 3 for a polygon. Modes that require a certain multiple of vertices are GL_LINES (2), GL_TRIANGLES (3), GL_QUADS (4), and GL_QUAD_STRIP (2). ERRORS GL_INVALID_ENUM is generated if mode is set to an unaccepted value. GL_INVALID_OPERATION is generated if glbegin is executed between a glbegin and the corresponding execution of glend. GL_INVALID_OPERATION is generated if glend is executed without being preceded by a glbegin. GL_INVALID_OPERATION is generated if a command other than glvertex, glcolor, glindex, glnormal, gltexcoord, glevalcoord, glevalpoint, glarrayelement, glmaterial, gledgeflag, glcalllist, or glcalllists is executed between the execution of glbegin and the corresponding execution glend. Execution of glenableclientstate, gldisableclientstate, gledgeflagpointer, gltexcoordpointer, glcolorpointer, glindexpointer, glnormalpointer, glvertexpointer, glinterleavedarrays, or glpixelstore is not (3 of 4) [24/09/ :49:35]

22 allowed after a call to glbegin and before the corresponding call to glend, but an error may or may not be generated. SEE ALSO glarrayelement, glcalllist, glcalllists, glcolor, gledgeflag, glevalcoord, glevalpoint, glindex, glmaterial, glnormal, gltexcoord, glvertex (4 of 4) [24/09/ :49:35]

23 NAME glbindtexture - bind a named texture to a texturing target C SPECIFICATION void glbindtexture( GLenum target, GLuint texture ) PARAMETERS target Specifies the target to which the texture is bound. Must be either GL_TEXTURE_1D or GL_TEXTURE_2D. texture Specifies the name of a texture. DESCRIPTION glbindtexture lets you create or use a named texture. Calling glbindtexture with target set to GL_TEXTURE_1D or GL_TEXTURE_2D and texture set to the name of the newtexture binds the texture name to the target. When a texture is bound to a target, the previous binding for that target is automatically broken. Texture names are unsigned integers. The value zero is reserved to represent the default texture for each texture target. Texture names and the corresponding texture contents are local to the shared display-list space (see glxcreatecontext) of the current GL rendering context; two rendering contexts share texture names only if they also share display lists. You may use glgentextures to generate a set of new texture names. When a texture is first bound, it assumes the dimensionality of its target: A texture first bound to GL_TEXTURE_1D becomes 1-dimensional and a texture first bound to GL_TEXTURE_2D becomes 2-dimensional. The state of a 1- dimensional texture immediately after it is first bound is equivalent to the state of the default GL_TEXTURE_1D at GL initialization, and similarly for 2-dimensional textures. While a texture is bound, GL operations on the target to which it is bound affect the bound texture, and queries of the target to which it is bound return state from the bound (1 of 3) [24/09/ :49:36]

24 texture. If texture mapping of the dimensionality of the target to which a texture is bound is active, the bound texture is used. In effect, the texture targets become aliases for the textures currently bound to them, and the texture name zero refers to the default textures that were bound to them at initialization. A texture binding created with glbindtexture remains active until a different texture is bound to the same target, or until the bound texture is deleted with gldeletetextures. Once created, a named texture may be re-bound to the target of the matching dimensionality as often as needed. It is usually much faster to use glbindtexture to bind an existing named texture to one of the texture targets than it is to reload the texture image using glteximage1d or glteximage2d. For additional control over performance, use glprioritizetextures. glbindtexture is included in display lists. NOTES glbindtexture is available only if the GL version is 1.1 or greater. ERRORS GL_INVALID_ENUM is generated if target is not one of the allowable values. GL_INVALID_OPERATION is generated if texture has a dimensionality which doesn't match that of target. GL_INVALID_OPERATION is generated if glbindtexture is executed between the execution of glbegin and the corresponding execution of glend. ASSOCIATED GETS glget with argument GL_TEXTURE_1D_BINDING glget with argument GL_TEXTURE_2D_BINDING SEE ALSO glaretexturesresident, gldeletetextures, glgentextures, glget, glgettexparameter, glistexture, glprioritizetextures, glteximage1d, glteximage2d, gltexparameter (2 of 3) [24/09/ :49:36]

25 (3 of 3) [24/09/ :49:36]

26 NAME glbitmap - draw a bitmap C SPECIFICATION void glbitmap( GLsizei width, GLsizei height, GLfloat xorig, GLfloat yorig, GLfloat xmove, GLfloat ymove, const GLubyte *bitmap ) PARAMETERS width, height Specify the pixel width and height of the bitmap image. xorig, yorig Specify the location of the origin in the bitmap image. The origin is measured from the lower left corner of the bitmap, with right and up being the positive axes. xmove, ymove Specify the x and y offsets to be added to the current raster position after the bitmap is drawn. bitmap Specifies the address of the bitmap image. DESCRIPTION A bitmap is a binary image. When drawn, the bitmap is positioned relative to the current raster position, and frame buffer pixels corresponding to 1's in the bitmap are written using the current raster color or index. Frame buffer pixels corresponding to 0's in the bitmap are not modified. glbitmap takes seven arguments. The first pair specifies the width and height of the bitmap image. The second pair specifies the location of the bitmap origin relative to the lower left corner of the bitmap image. The third pair of arguments specifies x and y offsets to be added to the current raster position after the bitmap has been drawn. The final argument is a pointer to the bitmap image itself. (1 of 3) [24/09/ :49:37]

27 The bitmap image is interpreted like image data for the gldrawpixels command, with width and height corresponding to the width and height arguments of that command, and with type set to GL_BITMAP and format set to GL_COLOR_INDEX. Modes specified using glpixelstore affect the interpretation of bitmap image data; modes specified using glpixeltransfer do not. If the current raster position is invalid, glbitmap is ignored. Otherwise, the lower left corner of the bitmap image is positioned at the window coordinates x = x - x w r o y = y - y w r o where (x,y ) is the raster position and (x,y ) is the bitmap origin. Fragments are then generated for each pixel corresponding to a 1 (one) in the bitmap image. These fragments are generated using the current raster z coordinate, color or color index, and current raster texture coordinates. They are then treated just as if they had been generated by a point, line, or polygon, including texture mapping, fogging, and all per-fragment operations such as alpha and depth testing. After the bitmap has been drawn, the x and y coordinates of the current raster position are offset by xmove and ymove. No change is made to the z coordinate of the current raster position, or to the current raster color, texture coordinates, or index. NOTES To set a valid raster position outside the viewport, first set a valid raster position inside the viewport, then call glbitmap with NULL as the bitmap parameter and with xmove and ymove set to the offsets of the new raster position. This technique is useful when panning an image around the viewport. ERRORS GL_INVALID_VALUE is generated if width or height is negative. GL_INVALID_OPERATION is generated if glbitmap is executed between the execution of glbegin and the corresponding (2 of 3) [24/09/ :49:37]

28 execution of glend. ASSOCIATED GETS glget with argument GL_CURRENT_RASTER_POSITION glget with argument GL_CURRENT_RASTER_COLOR glget with argument GL_CURRENT_RASTER_INDEX glget with argument GL_CURRENT_RASTER_TEXTURE_COORDS glget with argument GL_CURRENT_RASTER_POSITION_VALID SEE ALSO gldrawpixels, glpixelstore, glpixeltransfer, glrasterpos (3 of 3) [24/09/ :49:37]

29 NAME glblendcolorext - set the blend color C SPECIFICATION void glblendcolorext( GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha ) PARAMETERS GL_BLEND_COLOR_EXT red, green, blue, alpha specify the components of DESCRIPTION The GL_BLEND_COLOR_EXT may be used to calculate the source and destination blending factors. See glblendfunc for a complete description of the blending operations. Initially the GL_BLEND_COLOR_EXT is set to (0,0,0,0). NOTES glblendcolorext is part of the EXT_blend_color extension, not part of the core GL command set. If GL_EXT_blend_color is included in the string returned by glgetstring, when called with argument GL_EXTENSIONS, extension EXT_blend_color is supported by the connection. ERRORS GL_INVALID_OPERATION is generated if glblendcolorext is executed between the execution of glbegin and the corresponding execution of glend. ASSOCIATED GETS glget with an argument of GL_BLEND_COLOR_EXT. SEE ALSO glblendfunc, glgetstring. (1 of 2) [24/09/ :49:37]

30 (2 of 2) [24/09/ :49:37]

31 NAME glblendfunc - specify pixel arithmetic C SPECIFICATION void glblendfunc( GLenum sfactor, GLenum dfactor ) PARAMETERS sfactor Specifies how the red, green, blue, and alpha source blending factors are computed. Nine symbolic constants are accepted: GL_ZERO, GL_ONE, GL_DST_COLOR, GL_ONE_MINUS_DST_COLOR, GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_DST_ALPHA, GL_ONE_MINUS_DST_ALPHA, and GL_SRC_ALPHA_SATURATE. The initial value is GL_ONE. dfactor Specifies how the red, green, blue, and alpha destination blending factors are computed. Eight symbolic constants are accepted: GL_ZERO, GL_ONE, GL_SRC_COLOR, GL_ONE_MINUS_SRC_COLOR, GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_DST_ALPHA, and GL_ONE_MINUS_DST_ALPHA. The initial value is GL_ZERO. DESCRIPTION In RGBA mode, pixels can be drawn using a function that blends the incoming (source) RGBA values with the RGBA values that are already in the frame buffer (the destination values). Blending is initially disabled. Use glenable and gldisable with argument GL_BLEND to enable and disable blending. glblendfunc defines the operation of blending when it is enabled. sfactor specifies which of nine methods is used to scale the source color components. dfactor specifies which of eight methods is used to scale the destination color components. The eleven possible methods are described in the following table. Each method defines four scale factors, one each for red, green, blue, and alpha. In the table and in subsequent equations, source and destination color components are referred to as (R,G,B,A ) and (R,G,B,A ). They are understood to have integer values between 0dand (k,k,k,k ), where R G B A mc (1 of 4) [24/09/ :49:38]

32 kc = 2-1 and (mr,mg,mb,ma) is the number of red, green, blue, and alpha bitplanes. Source and destination scale factors are referred to as (s,s,s,s ) and (d,d,d,d ). The scale factors described in the table,gdenoted (f,f,f,f ), represent either source or destination factors.g All scale factors have range [0,1]. parameter (f, f, f, f ) GL_ZERO (0, 0, 0, 0) GL_ONE (1, 1, 1, 1) GL_SRC_COLOR (R /k, G /k, B /k, A /k ) GL_ONE_MINUS_SRC_COLOR (1, 1, 1,s1)R- (R /k, G /k, B /k, A /k ) GL_DST_COLOR (R /k, G /k, B /k, A /k ) s A GL_ONE_MINUS_DST_COLOR (1, 1, 1,d1)R- (R /k, G /k, B /k, A /k ) GL_SRC_ALPHA (A /k, A /k, A /k, A /k ) d A GL_ONE_MINUS_SRC_ALPHA (1, 1, 1,s1)A- (A /k, A /k, A /k, A /k ) GL_DST_ALPHA (A /k, A /k, A /k, A /k ) s A GL_ONE_MINUS_DST_ALPHA (1, 1, 1,d1)A- (A /k, A /k, A /k, A /k ) GL_SRC_ALPHA_SATURATE (i, i, i,d1)a d A d A In the table, i = min(a, k -A ) / k s A d A To determine the blended RGBA values of a pixel when drawing in RGBA mode, the system uses the following equations: R = min(k, R s +R d ) Gd = min(kr, GssR+GddR) Bd = min(kg, BssG+BddG) Ad = min(kb, AssB+AddB) d A s A d A Despite the apparent precision of the above equations, blending arithmetic is not exactly specified, because blending operates with imprecise integer color values. However, a blend factor that should be equal to 1 is guaranteed not to modify its multiplicand, and a blend factor equal to 0 reduces its multiplicand to 0. For example, when sfactor is GL_SRC_ALPHA, dfactor is GL_ONE_MINUS_SRC_ALPHA, and A is equal to k, the equations reduce to simple replacement:s A R = R (2 of 4) [24/09/ :49:38]

33 Gd = Gs Bd = Bs Ad = As d s EXAMPLES Transparency is best implemented using blend function (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA) with primitives sorted from farthest to nearest. Note that this transparency calculation does not require the presence of alpha bitplanes in the frame buffer. Blend function (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA) is also useful for rendering antialiased points and lines in arbitrary order. Polygon antialiasing is optimized using blend function (GL_SRC_ALPHA_SATURATE, GL_ONE) with polygons sorted from nearest to farthest. (See the glenable, gldisable reference page and the GL_POLYGON_SMOOTH argument for information on polygon antialiasing.) Destination alpha bitplanes, which must be present for this blend function to operate correctly, store the accumulated coverage. NOTES Incoming (source) alpha is correctly thought of as a material opacity, ranging from 1.0 (K ), representing complete opacity, to 0.0 (0), representing complete transparency. When more than one color buffer is enabled for drawing, the GL performs blending separately for each enabled buffer, using the contents of that buffer for destination color. (See gldrawbuffer.) Blending affects only RGBA rendering. It is ignored by color index renderers. ERRORS GL_INVALID_ENUM is generated if either sfactor or dfactor is not an accepted value. GL_INVALID_OPERATION is generated if glblendfunc is executed between the execution of glbegin and the corresponding execution of glend. ASSOCIATED GETS glget with argument GL_BLEND_SRC glget with argument GL_BLEND_DST glisenabled with argument GL_BLEND (3 of 4) [24/09/ :49:38]

34 SEE ALSO glalphafunc, glclear, gldrawbuffer, glenable, gllogicop, glstencilfunc (4 of 4) [24/09/ :49:38]

35 NAME glcalllist - execute a display list C SPECIFICATION void glcalllist( GLuint list ) PARAMETERS list Specifies the integer name of the display list to be executed. DESCRIPTION glcalllist causes the named display list to be executed. The commands saved in the display list are executed in order, just as if they were called without using a display list. If list has not been defined as a display list, glcalllist is ignored. glcalllist can appear inside a display list. To avoid the possibility of infinite recursion resulting from display lists calling one another, a limit is placed on the nesting level of display lists during display-list execution. This limit is at least 64, and it depends on the implementation. GL state is not saved and restored across a call to glcalllist. Thus, changes made to GL state during the execution of a display list remain after execution of the display list is completed. Use glpushattrib, glpopattrib, glpushmatrix, and glpopmatrix to preserve GL state across glcalllist calls. NOTES Display lists can be executed between a call to glbegin and the corresponding call to glend, as long as the display list includes only commands that are allowed in this interval. ASSOCIATED GETS glget with argument GL_MAX_LIST_NESTING glislist SEE ALSO glcalllists, gldeletelists, glgenlists, glnewlist, glpushattrib, glpushmatrix (1 of 2) [24/09/ :49:39]

36 (2 of 2) [24/09/ :49:39]

37 NAME glcalllists - execute a list of display lists C SPECIFICATION void glcalllists( GLsizei n, GLenum type, const GLvoid *lists ) PARAMETERS n type Specifies the number of display lists to be executed. Specifies the type of values in lists. Symbolic constants GL_BYTE, GL_UNSIGNED_BYTE, GL_SHORT, GL_UNSIGNED_SHORT, GL_INT, GL_UNSIGNED_INT, GL_FLOAT, GL_2_BYTES, GL_3_BYTES, and GL_4_BYTES are accepted. lists Specifies the address of an array of name offsets in the display list. The pointer type is void because the offsets can be bytes, shorts, ints, or floats, depending on the value of type. DESCRIPTION glcalllists causes each display list in the list of names passed as lists to be executed. As a result, the commands saved in each display list are executed in order, just as if they were called without using a display list. Names of display lists that have not been defined are ignored. glcalllists provides an efficient means for executing more than one display list. type allows lists with various name formats to be accepted. The formats are as follows: GL_BYTE GL_UNSIGNED_BYTE GL_SHORT lists is treated as an array of signed bytes, each in the range -128 through 127. lists is treated as an array of unsigned bytes, each in the range 0 through 255. lists is treated as an array of signed two-byte integers, each in the range through (1 of 4) [24/09/ :49:40]

38 GL_UNSIGNED_SHORT lists is treated as an array of unsigned two-byte integers, each in the range 0 through GL_INT GL_UNSIGNED_INT GL_FLOAT GL_2_BYTES GL_3_BYTES GL_4_BYTES lists is treated as an array of signed four-byte integers. lists is treated as an array of unsigned four-byte integers. lists is treated as an array of four-byte floating-point values. lists is treated as an array of unsigned bytes. Each pair of bytes specifies a single display-list name. The value of the pair is computed as 256 times the unsigned value of the first byte plus the unsigned value of the second byte. lists is treated as an array of unsigned bytes. Each triplet of bytes specifies a single displaylist name. The value of the triplet is computed as times the unsigned value of the first byte, plus 256 times the unsigned value of the second byte, plus the unsigned value of the third byte. lists is treated as an array of unsigned bytes. Each quadruplet of bytes specifies a single displaylist name. The value of the quadruplet is computed as times the unsigned value of the first byte, plus times the unsigned value of the second byte, plus 256 times the unsigned value of the third byte, plus the unsigned value of the fourth byte. The list of display-list names is not null-terminated. Rather, n specifies how many names are to be taken from (2 of 4) [24/09/ :49:40]

39 lists. An additional level of indirection is made available with the gllistbase command, which specifies an unsigned offset that is added to each display-list name specified in lists before that display list is executed. glcalllists can appear inside a display list. To avoid the possibility of infinite recursion resulting from display lists calling one another, a limit is placed on the nesting level of display lists during display-list execution. This limit must be at least 64, and it depends on the implementation. GL state is not saved and restored across a call to glcalllists. Thus, changes made to GL state during the execution of the display lists remain after execution is completed. Use glpushattrib, glpopattrib, glpushmatrix, and glpopmatrix to preserve GL state across glcalllists calls. NOTES Display lists can be executed between a call to glbegin and the corresponding call to glend, as long as the display list includes only commands that are allowed in this interval. ERRORS GL_INVALID_VALUE is generated if n is negative. GL_INVALID_ENUM is generated if type is not one of GL_BYTE, GL_UNSIGNED_BYTE, GL_SHORT, GL_UNSIGNED_SHORT, GL_INT, GL_UNSIGNED_INT, GL_FLOAT, GL_2_BYTES, GL_3_BYTES, GL_4_BYTES. ASSOCIATED GETS glget with argument GL_LIST_BASE glget with argument GL_MAX_LIST_NESTING glislist SEE ALSO glcalllist, gldeletelists, glgenlists, gllistbase, glnewlist, glpushattrib, glpushmatrix (3 of 4) [24/09/ :49:40]

40 (4 of 4) [24/09/ :49:40]

41 NAME glclear - clear buffers to preset values C SPECIFICATION void glclear( GLbitfield mask ) PARAMETERS mask Bitwise OR of masks that indicate the buffers to be cleared. The four masks are GL_COLOR_BUFFER_BIT, GL_DEPTH_BUFFER_BIT, GL_ACCUM_BUFFER_BIT, and GL_STENCIL_BUFFER_BIT. DESCRIPTION glclear sets the bitplane area of the window to values previously selected by glclearcolor, glclearindex, glcleardepth, glclearstencil, and glclearaccum. Multiple color buffers can be cleared simultaneously by selecting more than one buffer at a time using gldrawbuffer. The pixel ownership test, the scissor test, dithering, and the buffer writemasks affect the operation of glclear. The scissor box bounds the cleared region. Alpha function, blend function, logical operation, stenciling, texture mapping, and depth-buffering are ignored by glclear. glclear takes a single argument that is the bitwise OR of several values indicating which buffer is to be cleared. The values are as follows: GL_COLOR_BUFFER_BIT GL_DEPTH_BUFFER_BIT GL_ACCUM_BUFFER_BIT GL_STENCIL_BUFFER_BIT Indicates the buffers currently enabled for color writing. Indicates the depth buffer. Indicates the accumulation buffer. Indicates the stencil buffer. NOTES The value to which each buffer is cleared depends on the setting of the clear value for that buffer. (1 of 3) [24/09/ :49:41]

42 If a buffer is not present, then a glclear directed at that buffer has no effect. ERRORS GL_INVALID_VALUE is generated if any bit other than the four defined bits is set in mask. GL_INVALID_OPERATION is generated if glclear is executed between the execution of glbegin and the corresponding execution of glend. ASSOCIATED GETS glget with argument GL_ACCUM_CLEAR_VALUE glget with argument GL_DEPTH_CLEAR_VALUE glget with argument GL_INDEX_CLEAR_VALUE glget with argument GL_COLOR_CLEAR_VALUE glget with argument GL_STENCIL_CLEAR_VALUE SEE ALSO glclearaccum, glclearcolor, glcleardepth, glclearindex, glclearstencil, gldrawbuffer, glscissor (2 of 3) [24/09/ :49:41]

43 (3 of 3) [24/09/ :49:41]

44 NAME glclearaccum - specify clear values for the accumulation buffer C SPECIFICATION void glclearaccum( GLfloat red, GLfloat green, GLfloat blue, GLfloat alpha ) PARAMETERS red, green, blue, alpha Specify the red, green, blue, and alpha values used when the accumulation buffer is cleared. The initial values are all 0. DESCRIPTION glclearaccum specifies the red, green, blue, and alpha values used by glclear to clear the accumulation buffer. Values specified by glclearaccum are clamped to the range [-1,1]. ERRORS GL_INVALID_OPERATION is generated if glclearaccum is executed between the execution of glbegin and the corresponding execution of glend. ASSOCIATED GETS glget with argument GL_ACCUM_CLEAR_VALUE SEE ALSO glclear (1 of 2) [24/09/ :49:41]

45 (2 of 2) [24/09/ :49:41]

46 NAME glclearcolor - specify clear values for the color buffers C SPECIFICATION void glclearcolor( GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha ) PARAMETERS red, green, blue, alpha Specify the red, green, blue, and alpha values used when the color buffers are cleared. The initial values are all 0. DESCRIPTION glclearcolor specifies the red, green, blue, and alpha values used by glclear to clear the color buffers. Values specified by glclearcolor are clamped to the range [0,1]. ERRORS GL_INVALID_OPERATION is generated if glclearcolor is executed between the execution of glbegin and the corresponding execution of glend. ASSOCIATED GETS glget with argument GL_COLOR_CLEAR_VALUE SEE ALSO glclear (1 of 2) [24/09/ :49:42]

47 (2 of 2) [24/09/ :49:42]

48 NAME glcleardepth - specify the clear value for the depth buffer C SPECIFICATION void glcleardepth( GLclampd depth ) PARAMETERS depth Specifies the depth value used when the depth buffer is cleared. The initial value is 1. DESCRIPTION glcleardepth specifies the depth value used by glclear to clear the depth buffer. Values specified by glcleardepth are clamped to the range [0,1]. ERRORS GL_INVALID_OPERATION is generated if glcleardepth is executed between the execution of glbegin and the corresponding execution of glend. ASSOCIATED GETS glget with argument GL_DEPTH_CLEAR_VALUE SEE ALSO glclear (1 of 2) [24/09/ :49:42]

49 (2 of 2) [24/09/ :49:42]

50 NAME glclearindex - specify the clear value for the color index buffers C SPECIFICATION void glclearindex( GLfloat c ) PARAMETERS c Specifies the index used when the color index buffers are cleared. The initial value is 0. DESCRIPTION glclearindex specifies the index used by glclear to clear the color index buffers. c is not clamped. Rather, c is converted to a fixed-point value with unspecified precision to the right of the binary point. The integer part of this value is then masked with 2m-1, where m is the number of bits in a color index stored in the frame buffer. ERRORS GL_INVALID_OPERATION is generated if glclearindex is executed between the execution of glbegin and the corresponding execution of glend. ASSOCIATED GETS glget with argument GL_INDEX_CLEAR_VALUE glget with argument GL_INDEX_BITS SEE ALSO glclear (1 of 2) [24/09/ :49:43]

51 (2 of 2) [24/09/ :49:43]

52 NAME glclearstencil - specify the clear value for the stencil buffer C SPECIFICATION void glclearstencil( GLint s ) PARAMETERS s Specifies the index used when the stencil buffer is cleared. The initial value is 0. DESCRIPTION glclearstencil specifies the index used by glclear to clear the stencil buffer. s is masked with 2m-1, where m is the number of bits in the stencil buffer. ERRORS GL_INVALID_OPERATION is generated if glclearstencil is executed between the execution of glbegin and the corresponding execution of glend. ASSOCIATED GETS glget with argument GL_STENCIL_CLEAR_VALUE glget with argument GL_STENCIL_BITS SEE ALSO glclear (1 of 2) [24/09/ :49:43]